Clinical Considerations in the Diagnosis of Autism Spectrum Disorders

Clinical Considerations in the Diagnosis of Autism Spectrum Disorders Gillian Baird) Tony Charman 2and Paramala Janardhanan Santosh 3 1Newcomen Centr...
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Clinical Considerations in the Diagnosis of Autism Spectrum Disorders Gillian Baird) Tony Charman 2and Paramala Janardhanan Santosh 3

1Newcomen Centre Guys and St Thomas" Trust 2Behavioural Sciences Unit, Institute of Child Health 3Academic Department of Child & Adolescent Psychiatry, Institute of Psychiatry, London Abstract. The diagnosis of autistic spectrum disorders (ASD) is being made more frequently in children and at younger ages. This paper discusses various factors to be considered in the screening of autism, early features of presentation, relevant to assessment and diagnosis, subtypes or different syndromes ithin the spectrum of autistic conditions including Asperger syndrome, the differential diagnosis from learning and language disorders and the medical and behavioural commonly associated disorders.[Indian J Pedlatr 2001; 68 (5) : 439-449]

Key words : Autistic spectrum disorders; Asperger syndrome; Intelligence quotient (IQ) Autism is a biologically-based neurodevelopmental condition more common in males with a characteristic behavioural pattern and cognitive style that is life long but varied in its manifestations with age. Once thought to be a categorical disorder, there is an increasing consensus that the defining characteristics should be considered as dimensional features within a broad behavioural phenotype. 1,2 Childhood autism is the prototypic disorder in the spectrum of autistic disorders. 3'4 All disorders within the autistic spectrum are characterised by : (i) qualitative impairments in social interaction shown in the use of non verbal behaviours such as eye gaze and body posture to regulate social interaction, a failure to develop peer relationships, a lack of spontaneous showing and sharing of interests and a lack of social emotional reciprocity; and (ii) qualitative impairments in social commtmication shown by a delay in language development without non-verbal compensation; problems initiating and sustaining conversations, repetitive and stereotyped use of language and a lack of varied and imaginative or imitative play. In addition there is (iii) a restricted repertoire of interests and behaviours and activities as shown by an abnormal overfocus or intensity of interest in particular topics which amounts to a preoccupation, an adherence to non functional routines or rituals, repetitive stereotyped motor mannerisms and a preoccupation with parts of objects or the detail rather Reprint requests : Dr. GiUian Baird, Newcomen Centre Guy's and St.Thomas' Trust, London SE1 9RT. E-marl : [email protected]

Indian Journal of Pediatrics, Volume 68--May, 2001

than the whole. Sensory abnormalities including either hypo-sensitivity or hyper-sensitivity and unusual interests in some sensations are commonly found. A lack of imaginative play indicates an underlying difficulty with generation of ideas, which is highly relevant in the development of understanding of, and thinking about, other people and other situations etc. All of these characteristics can be seen in varying degrees of severity. For example, a child may present with little or no language, or may present with a lot of language but still lack knowledge and understanding of the rules of reciprocity and communication, and so may talk all the time about something of particular interest to them, without listening to or being aware of partner response. 5 Prevalence

The prevalence of childhood autism originally considered to be 4 per 10,0006 has now been revised upwards as children with a broader range of difficulties in the above triad of impairments are included. A recent review by Fombonne7 gives a figure of 16 per 10,000 for disorders in the broader spectrum. A higher figure still of over 1% arises from studies by Gillberg, which includes Asperger's syndrome and other autistic-like disorders?,9The Checklist for Autism in Toddlers (CHAT) follow-up study, although all diagnoses are not yet confirmed, found a figure of approximately 0.5% of the childhood population? ~ There has been-much debate about whether the prevalence of autism is truly increasing. 11 There is

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certainly better and earlier recognition of the disorder, diagnostic criteria have also changed and one suspects that some of the children in Lotter's original groups whom he excluded from a final diagnosis of autism would now be included.6

Diagnostic Criteria and Subtypes The ICD-10 and DSM-IV classification systems are now similar in their descriptions of core autism. There are both clinical and research reasons why subgrouping within the spectrum of autistic disorders might be desirable, comparison of particular groups of children from one geographic area to another, different prognosis, different methods of management, a different aetiology or neuropsychological underpinning or different associated comorbidities. Amongst experts there is high agreement about a diagnosis of childhood autism 12 but less clear agreement about atypical autism and the group classified as PDDNOS? 3 While Asperger's syndrome14 has been a useful clinical description, it remains a diagnosis of uncertain nosological validity. Wing has described the behavioural sub-types of "aloof", "passive" and "active but-odd" children, is There is some evidence that as children develop they become less aloof and passive and more active-but-odd. This subtypology has not been directly compared to that in the formal classification systems. The AACAP Practice Parameters TMenjoin clinicians to differentiate autism and the other PDD's from each other as well as from other specific developmental disorders but recent reviews and papers have all indicated the great difficulty for example of clear differentiation of Asperger's from high functioning autism 17'19"2~and especially over time. The concerns are that subgroups are being differentiated on past history for example language milestones and abnormalities prior to three years versus current behaviours, cognitive level, neuropsychological findings or comorbidities. Variable application of the hierarchical principle i.e. that if a child meets criteria for autism that is the diagnosed is has added to the problems. Varying classifications systems will include different groups of children using, for example, the Szatmari criteria2zand GiUberg criteria.22Those of ICD-10 and DSM-IV also overlap with the clinical description of the Schizoid Personality of Childhood. 23 KuglerTMhas suggested that clinically there are some specific differences between Asperger's syndrome, and individuals with autism with average intelligence and fluent language ("high functioning autism"). These are more frequently showing delayed motor milestones and clumsiness; less echolalic speech, fewer instances 440

of pronominal reversal and repetitive speech, richer conversation and more complex but pedantic verbosity; more commonly an all absorbing interest but less insistence on sameness, fewer stereotypes and a greater imagination. Further she suggested that in Asperger's syndrome interests are more likely to be shared, there is more affection and more peer interest even though peer success may be lacking. Cognitively, verbal IQ is usually higher than performance IQ (the opposite pattern to that found in most individuals with autism) with deficits in visuo-motor abilities and nonverbal concepts more common in the Asperger's syndrome group. On the other hand, as Mangevion and Prior 17point out, if the differential diagnosis of Asperger's syndrome from autism is made on the basis of early language milestones it is not surprising that at a later stage verbal IQ is found to be greater than in the higher functioning autism group who have usually had quite a marked delay in the acquisition of language skills. Their study found no differences in neuropsychological measures between the two groups. However, many clinicians will find that the above features are the bases on which they make a distinction if they do at all, of Asperger's syndrome versus high functioning autism. In addition, it is a term which does provide parents with access to both more immediately suitable literature and parent groups with whom they can find more in common. Klin et a124have pointed out the similarities of neuropsychological profiles of individuals presenting with non verbal or "right hemisphere" learning difficulties, 25and Asperger, syndrome where there are particular deficits in fine and gross motor skills, visuospatial perception, visuo-motor integration, visual memory, verbal/non-verbal concept formation, the prosody, pragmatics and verbal content of spoken language, reading comprehension and mechanical arithmetic; whereas the assets are those of rote memory, auditory verbal learning, phonology vocabulary, verbal output and spelling. Other possible differentiating features of the group with Asperger syndrome is that they may be more likely to have comorbid ADHD and, certainly from clinical experience, quite likely to present with early features which results in an initial diagnosis of ADHD. There may be more obsessive compulsive behaviours, more social phobia, affective disorders and generally higher rates of psychiatric problems. The possibility of a different family phenotype between Asperger's syndrome and Autism has been raised, with possibly more social difficulties in male family members, although these factors have yet to be systematically investigated in suitable family cohorts to provide a definitive answer. An additional point of discussion has been that of Indian Journal of Pediatrics, Volume 68--May, 2001

Diagnosis of Autism Spectrum Disorders

the overlap with children who present with what seems more of a problem in language understanding and use. Semantic and pragmatic language impairment was initially suggested as an entirely separate disorder. 26However, the overlap in presentation with autism spectrum conditions, and the medium to long term social impairments which these children experience, combined with other aspects of behaviour such as rigidity of behaviour, restricted interests etc. means that most clinicians now include this group among the various disorders on the autistic spectrum. Clinically this group shows rather better motivation and social awareness, with milder socio-cognitive deficits coupled with more severe pragmatic and semantic impairments in language. There is an invariable history of delayed phrase speech although the onset of single words may well have been appropriate in timing. 27 To ensure comparability of assessment, many research groups use semi-structured parental interviews such as the Autism Diagnostic InterviewRevised (ADI-R)2sand structured interaction schedules such as the Autism Diagnostic Observation ScheduleGeneric (ADOS-G) 29. For clinical work, additional description of IQ and language levels is required. The Vineland Adaptive Behaviour Scales~gives a measure of adaptive behaviour and current functioning, together with a maladaptive behaviour scale. Several other measures of autism have been in use for a number of years, for example, the Autism Behaviour Checklist (ABC)31 and the Childhood Autism Rating Scale (CARS) 32both with good inter-reliability. Most recently the Diagnostic Interview for Social and Communication Disorders (DISCO) 19 has been developed out of Wing's previous research and is a comprehensive tool for clinical assessment, covering a very wide number of areas of behaviour and function.

Early Recognition and Screening Many children are now diagnosed as having an autistic spect~m disorder in the preschool years. 33 Symptom onset before the age of 3 is required for a diagnosis of childhood autism. Diagnosis is usually above the age of 5 for Asperger's syndrome, in line with the fact that an absence of impairment of cognitive, gross language and adaptive skills is required by ICD-10. In general it is the higher functioning children who are diagnosed at an older age, particularly those where language delay is not such art obvious early feature. Early diagnosis is desirable for a number of reasons. Parents are very anxious to understand their children's behaviour, in it also allows the opportunity for discussions about causation and genetic counselling if wished, s4 The Indian Journal of Pediatrics, Volume 68--May, 2001

results of intervention studies suggest that well targeted pre-school intervention, at as young an age as possible, appear to be associated with better outcome. 35-4~Although there has been controversy about some of the studies of behaviourally orientated early intervention programmes, 41,~2there is broadbased agreement that there are many gains in the short-term. However, few studies have produced long term follow-up, and in those that have, there are methodological limitations. A consensus document from the United States has laid out guidelines for screening, diagnosis and methods of investigation proposed at primary and secondary level. 43,~ One area of recommendation is directed towards screening. Screening is the presumptive identification of unrecognised disease or defect by the application of tests and attempts to sort out those who are at greater risk of a disorder or disease, that those who are not. Thus it is important to distinguish the kinds of activities which start from a premise that something is completely unrecognised by parents and the situation in which one is responding to parental concern using a checklist of symptoms. Screening of the total population can be done by using general developmental checklists in which parents are asked for their view and / or in which specific tests and observations are made of the child by a professional; or there can be focused screens adopting the same approach but specific for autism. 45 Several studies have confirmed that for many parents concerns began to crystallise during the second year at around about 18 months. There is evidence both of a lack of acquiring particular developmental skills and unusual behaviours. For example, a lack of social interest in peers, delayed speech without use of gestures including pointing a lack of social sharing, giving and social imitation and no imaginative play have all been reported in retrospective parental accounts of first symptoms. ~ In addition, a restricted range of interests that are often repetitive, mannerisms and sensory sensitivities are all noted early features. Analysis of early videotaped material taken before a diagnosis was suspected47has shown that there is a lack of social smiling, a lack of appropriate facial expression, poor attention, impaired social interaction, all which could be noted in the first year; plus an ignoring of people, preference for londiness, lack of eye contact, lack of appropriate gestures and lack of emotional expression, less looking at others, less pointing and less showing of objects in the second year. Items of developmental history which appear to be discriminating are noted by several from surroundings, failure to play like other children, apparent deafness, empty gaze, failure to attract attention, lack of smiling 441

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and poor imitation of movements.~ A poor response to others, apparent deafness and poor peer relationships have also been noted as early signs of autism. 49Lord has confirmed in her follow-up study of two-year-olds, the above discriminating items and also noted that separation anxiety and abnormalities of attachment are not necessarily discriminating features at that age. s~ Unusual behaviours that discriminate are: abnormal orientation to visual stimuli, aversion to touch and a failure to orientate to the name. The USA consensus on screening recommends that developmental disorders should be systematically looked for by the health service and that parental concerns should be listened and responded to. Very few general developmental screens have reported their success or otherwise at specifically finding autistic spectrum disorders. On the whole, low sensitivity and specificity for other developmental problems is the norms (e.g. Denver Developmental Screening Test). There is a problem in developmental disorders of definition of "caseness" generally, where the 'reference test' is often a clinical opinion. Glascoe in a series of papers sl,s2has reported the results of the Parents' Evaluations of Developmental Status (PEDS) which asks parents for their concerns in a n u m b e r of different areas of development. An algorithm has been developed and Glascoe reports that there is a 75-80% sensitivity of detecting childhood disabilities and a 70-80% specificity to normal development. One important finding is that where parents have two or more significant concerns, it is best to refer the child straight away for a more-in-depth assessment rather than applying a further screen. The Checklist for Autism in Toddlers (CHAT) is a specific screening instrument for autism which has been used in a total population in the UK, where screening is done largely by Health Visitors at specific times in the preschool years. 1~ Its format is a mix of parent questions and Health Visitor elicited observations of the child. The questions were not open-ended to parents as on the PEDS but were very specifically looking for particular developmental skills at 18-20 months. The key items in both the parent question and the health visitor observation sections were those asking about pointing, particularly pointing for shared interest, following the adult pointing at something by turning the eyes to gaze at the referred object and pretending. A population of over 16,000 children was screened at the age of 18-20 months. There was a two stage procedure to recheck the findings of failure on these items after one month in order to ensure that these were persistent failings, rather than a developmental stage which was emergent. The children were all followed-up to the age 442

of between 6-7 years. The results were assessed in terms of high-risk status, where the children failed all the key items, and a medium risk status, where d'dldren failed pointing for interest only. The results showed that for the 2stage procedure the sensitivities were 18% (9/50) and 20% (10/50) for high and medium risk for all PDD. The figures for the 1-stage screen only were 20% and 38%. Specificity was 99%. The failure to pick up a significant proportion of childhood autism from the general population at the age of 18-20 months was due to a number of factors, including parents not recognising that there was an impairment and reporting that the children did demonstrate skills which subsequently they felt they probably had not yet acquired. Also looking for delays in a number of developmental milestones means that children who are higher functioning are likely to have achieved the milestones by 18-20 months, although perhaps not entirely normal nor with normal frequency. The sensitivity of the CHAT in this study means that one could not recommend screening at one point in time with a specific instrument as being an appropriate use of resources, or the best way to pick up all children with a pervasive developmental disorder. However in a subsequent study where Health Visitors were asked to use the key items of following gaze, pointing and pretence and were also asked to exercise their clinical judgement as to whether or not on examining the child for these skills, they felt there was a significant difficulty and if the parent agreed, the child was then referred. This gave nearly 80% positive predictive value of all PDD and a 98% positive predictive value of any developmental disorder. What this indicates is that a failure to gain these key developmental milestones by this age is highly relevant and something that should be taken note of. Many of the "screening instruments" being developed in the USA are being used as secondary screens once a problem in social communicative area is suspected (e.g. PDDST, s4 the M-CHAT an extension of the original CHAT study.) ss Many parents do notice impairments in the first year and this is particularly so if they have had an older child who has developmental problems. There are however a significant proportion of children who show apparently normal development in the first year and then a stasis of skills or frank regression in the second year. The skills that are lost tend most obviously to be acquired language (which is usually at the tess than 10 word stage) there may be much less use of eye gaze and even the avoidance of eye gaze combined with increased aloneness, social avoidance and sometimes the onset of repetitive play activities. There is rarely Indian Journal of Pediatrics, Volume 68---May, 2001

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loss of either fine or gross motor skills. Some parents report changes of sleeping and eating behaviours. The rates of regression vary from 15% to nearly 50% across different samples and the younger the child is at the time a detailed history is taken the more likely the parent is to report stasis or even loss of skills.56'57The peak age at regression is 15-20 months. Some children regress at a later age anywhere between 3 and 10 years, following a prolonged period of normal development in language social and play skills. Regression at this stage (where it is not what is sometimes referred to as late onset autism - which in many cases may well be the delayed recognition of abnormality rather than a normal child showing regression) is very much more devastating with a poorer outcome both in cognitive and social terms. This is also referred to as "Heller's disintegrative psychosis". A very small subgroup of these children will have a degenerative neurological disorder but most do not. 58 In summary, it is clear that there are a number of features of acquisition of appropriate developmental milestones in the areas of socialisation and communication which become most apparent during the second year of life and subsequently. While it is relatively easy to see these with hindsight, the process of systematically detecting them as part of total population screening is not easy. Once the parent or professional is alerted to a developmental delay or difficulty in these areas, and most particularly any history of regression, there are now many good tools for assessment at a very young age. By the use of systematic observation and history, combined with informed and experienced clinical opinion, a diagnosis is both possible and reliable at this stage, s~176 Most autistic disorders, however, will not be detected by the application of strict screening criteria. They are more likely to be detected by the raising of awareness of what is expected in normal development among both parents and professionals in a wide variety of settings, and the informed and rapid response to any concern about any social communicative impairment. The same comment can be applied to screening older children i.e. those in school. Ehiers and Gillberg reported the use of their screening instrument for Asperger syndrome 8,61in a population of 1400. This screening test plus the Australian Scale for Asperger syndrome62are again most likely to be used as a second stage screening once the functional problem has been highlighted rather than by the application of screening to a total population. Both questionnaires are useful for this purpose. Differential Diagnosis

The differential diagnosis of a possible developmental Indian Journal of Pediatrics, Volume 68---May, 2001

disorder on the autistic spectrum is extensive in clinical child development practice. The difficulties that tend to cause problems are as follows : 1. Mental retardation/general learning disability. 2. Language disorders, especially receptive disorders. 3. Mixed developmental disorders, including dyspraxia, ADHD, DAMP and mild learning problems, which are frequently associated with mixed developmental disorders. 4. Deafness should not be a problem but needs to be excluded. General Learning Disability

The prevalence of a disorder on the autistic spectrum is increased in those with learning disability, from 12% in individuals with mild to moderate disability to 30% in individuals with severe learning disability. 63Equally there is a higher prevalence of learning disability in autism, although as the diagnosed spectrum has broadened, the number with normal range abilities rises. Levels of learning difficulty in autism have been previously quoted as 75% with an IQ less than 70~ with perhaps 47% having severe or profound learning difficulties and 24% mild to moderate learning difficulties.6s One can summarise by saying that the likelihood of an autistic spectrum disorder rises with falling IQ, the male/female ratio falls with falling IQ, and that a diagnosis of an autistic disorder is much less likely to be made in the presence of physical disability or profound mental retardation. In the Wing and Gould Camberwell study, the prevalence of an autistic spectrum disorder with an IQ of less than 70, was 21 per 10,000.5 Considering the subtypes of autistic disorder found in the learning disabled, a diagnosis of Asperger syndrome is for many people (and in the classification systems) excluded by having an IQ of less than 70, although this is much debated. 66Autism often appears atypical and not necessarily meeting criteria across all domains, and the ICD-10 but not the DSM-IV, recognises a subgroup who have motor stereotypes in severe mental retardation, as part of the pervasive developmental disorders. There has been a debate about why it is necessary to diagnose an autistic disorder in those who have significant learning disabilities. One very important reason from the parental perspective is that it influences how the child behaves. There has been much debate about whether this diagnosis then makes a difference to the type of school that is recommended. This of course depends very much on local expertise and resources but it certainly makes a difference to the way in which one plans an educational programme, the kind of 443

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Symptom Social relatedness Social relatedness Pointing and understanding gestures

Autism + Learning Difficulties

Learning Difficulties

Ignoring persons, difficult to engage

Easy to engage and takes notice of people

Poor

Good Points and uses gestures

Poor, may use parts of anothers' body as tool

Eye Gaze

Less eye gaze even in teasing

Use eye gaze in teasing

Play

Less functional, more repetitive use of objects

More functional and symbolic Play

Mannerisms

More stereotyped movements and hand mannerisms

Sensitivities

More sound sensitivities and ignoring of other people speaking

environment that may or may not be required, the degree of structure, predictability and visual communication that is needed. While in the very young or very profoundly delayed child, differentiating autism plus learning disability from learning disability alone may be difficult, there are a number of features that may help.

Language Disorders Particular problems are encountered with children who have receptive language impairments. The important longitudinal study of Rutter and colleagues67~9 indicates the long-term social impairments of a group of children originally thought only to have language difficulties. There is increasing evidence that children with specific language impairments not only have difficulty in processing language but may also have difficulty in processing other kinds of communicative information.7~ Children presenting with receptive language problems may also require adherence to routines, have limited imaginative play skills and peer based social impairment. A recent follow-up study~ indicated that where these features have been present even at the age of 3 or 4 even though there had been progress with language learning, the social impairments remained very significant and signs of an autistic disorder became more marked into middle childhood. Volkmar and colleagues have described features that can differentiate a language disorder and ASD72 Social : Inability to make friends, chooses solitary 444

activities, empathy deficit, impaired imitation, lack of sociability, no close friends, indifference to praise. Communication : Lack of social use of language, impaired make-believe and peculiar speech pattern. Response to environment : Need to maintain sameness, resistant to change, insistence on routines and hyper/ hypo sensitivity, bizarre response to the environment. Affective : Social anxiety, emotional libility and inappropriate affect.

Other Specific Developmental Disorders Perhaps the most c o m m o n of these is a motor impairment, currently classified as a Developmental Co-ordination Disorder. There is some evidence that it is the area of praxis that is particularly impaired, i.e. the planning, organisation and execution of complex motor tasks although it is the gestures and body postures of social behaviour that are often noted to be impaired. Although thought to be particularly associated with Asperger syndrome, incoordination can occur in any of the autistic spectrum disorders. The difficulty in writing creates a major barrier to output for many high functioning children. Increasingly this results in the practical suggestion to use a lap-top computer which has the great advantage of getting around a problem which often threatens to affect the attitude of the child to the entire educational process. Other specific learning difficulties such as reading can also co-occur with autism spectrum disorders. Each of these areas of difficulty needs assessments and Indian Joumal of Pediatrics, Volume 68--May, 2001

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management suggestions in their own right. Other disorders, co-morbid or causing diagnostic difficulty include : 1. Reactive attachment disorders of childhood following early emotionally depriving experiences. There may be behavioural similarities in difficulties with empathic learning and behaviour. Early childhood experiences such as those in Romanian Orphanages can be associated with many overlapping behaviours but also differences from autism. 73'74 2. Diagnosis of comorbid autistic behaviours in those who are blind. 3. Oppositional Defiant Disorder and Conduct Disorder can be an add~'onal comorbidity, particularly when there has been an earlier associated Attention Deficit Disorder with or without hyperactivity. While easier to recognise in boys, there are some features found in some girls, fantasy behaviour, which, combined with the perception of the adult that there is a level of social knowing and social manipulation unusual in the pervasive developmental disorders, has led Newson to describe a "Pathological Demand Avoidance Syndrome'. Part of the spectrum of PDD, this group lack social motivation to conform to expected social norms, despite average intelligence, and show constantly changing behaviours and appear able to adapt to any strategy adopted by the adult. Medical Conditions and Autism While there is now broad agreement that there is a substantial genetic predisposition to autism, with high concordance in identical twins in twin studies 77,78and with a broader phenotype in extended families, 79'8~ there are a number of medical conditions that are associated with autism in a causative way or where autism is part of the behavioural manifestation. 8] Causative conditions are found less frequently in autism compared with a developmentally delayed non-autistic group (12% in autism versus 22%). Increased medical conditions tend to be found with decreasing IQ, and medical conditions tend to increase with a broader autistic spectrum disorder definition rather than when narrowly defined autism is used. There is variability in studies in the frequency of medical findings that are felt to be causative of autism, and variability in the definition of autistic disorder used. Currently the evidence w o u l d support the recommendation of a general physical examination including viewing with Woods Light to look for white patches suggestive of tuberous sclerosis, biochemistry and metabolic tests as per mental retardation protocols. N e u r o i m a g i n g is not routinely r e c o m m e n d e d in autism, unless there is another neurological Indian Journal of Pediatrics, Volume 68---May, 2001

indication.82Macrocephaly is more commonly found. Chromosomes, including Fragile-X, should be requested on everybody, although Fragile-X is not c o m m o n in autism and other chromosome abnormalities appear to be commoner in the broader ASD group. If there is a history of pica it is helpful to do a serum lead assay. Hearing tests will be required in all cases, frequently using brain stem evoked responses. Epilepsy and Autism One third of individuals with autism are likely to develop epilepsy at some time in their lives - - a higher proportion following a late disintegrative disorder. There is a significant relationship with IQ, and the longer the follow-up the greater is the incidence of epilepsy. The presence of epilepsy combined with learning disability in a child means that the likelihood of an additional autistic-like condition including autism will be found in a third, and of the entire spectrum of autistic behaviour in nearly half. There is a high comorbidity with self-injurious behaviour and poorer long-term outcome for individuals with epilepsy. 75 The relationship of epilepsy to early regression is as yet unclear. Tuchman and Rapin 57 have examined the largest cohort of children (n = 585), 30% of whom had a history of regression and 11% with epilepsy. Regression occurred with the same frequency in those with and without epilepsy. When those who were definitely epileptic were excluded but had a sleep EEG recorded, 19% of those who regressed showed epileptiform activity on their EEG compared with 10% without regression (epileptiform being defined as any spike discharges or paroxysmal spike wave discharges), 50% were centro-temporal. These findings have to be set in the context of a study of normal young adults where all possible neurological disease was excluded but where the vast majority were found during sleep EEG to have an epileptiform discharge most of them in the fronto-temporal region.76 Sleep EEG is currently recommended in children who have a history of loss of language skills in the second year, although as discussed above the significance of any epileptiform EEG is unknown and there are only occasional single case studies of treatment with anti-epileptic drugs. There have been suggestions of epileptic syndromes and autism overlapping with Llandau Kleffner S y n d r o m e acquired epileptic aphasia (although continuous spike wave discharge is rarely found in autism).~ There have been some reports of subpial transection (MST) with variable result. 84This is an area where caution and further research is needed and where a course of fluctuating behaviours is crucial in clinically 445

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prompting an EEG investigation.~ The lack of clear medical causation of autism in m a n y i n d i v i d u a l s , c o m b i n e d w i t h the g r a d u a l recognition or onset with regression in the second year of life, has prompted many parents to look for other causes. For example, the apparent onset coincides with the MMR vaccination and combined with reports of associations with bowel disorder has led to fears of immunisation.~,87 Other Behaviours

Learning disorders in children are a risk factor for behaviour problems. An Australian study found that 41% of those with mild, moderate or severe learning difficulties had severe emotional or behavioural disturbance. 88Self-absorbed autistic behaviour was found more commonly the more severe the learning difficulty, whereas disruptive behaviour was commoner in the mild to moderate learning difficulty group. In the high functioning autism group, a recent study by Szatmari and colleagues found that 17% scored more than 2 standard deviations above the population mean both for ADHD and depression, and 13.5% for anxiety. 89 Commonly found behaviour problems in the group of children with autism spectrum disorder are regressive and challenging behaviours, attentional problems with or without hyperactivity, self-injury, obsessive compulsive behaviour, sleeping and eating problems and anxious behaviour sometimes with fears amounting to phobias. While it is important to take a broad clinical approach to the understanding of the behavioural problem, and to consider in a logical way the traditional behavioural approaches e.g. within-person predisposing factors and the precipitating and maintaining factors to the behaviour itself, it is also important to consider autismspecific behaviours where overt externalised behaviour is frequently a form of communication in response to change, sensory sensitivity, obsession and a rigid cognitive style. Pharmacology for particular symptoms can be helpful and these are broadly divided into the following groups (see 90 and 91 for reviews): 1. 2. 3. 4.

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The anti-epileptic drugs for epilepsy and also for mood stabilisation. SSRI's for obsessive compulsive symptoms, and in change-precipitated behaviour'. Stimulants for ADHD. Psychotropics are most often used for aggressive behaviour and it is salutary that more learning disability children and adults with autism spectrum disorders are prescribed anti-psychotic than those who have learning disability without

5.

autistic disorder. Specific treatments for sleep problems - such as melatonin and trazodone

There are a few studies of the effects of this broad range of medication in children with learning disabilities and those studies that have been done tend to be on small groups. CONCLUSION The value to the child and family of an accurate diagnosis of a disorder on the autistic spectrum is that of understanding the child's behaviour and learning patterns, hence being able to meet his or her needs more effectively both within the family and school. These disorders have a life long impact and even for those who are more able, the outcome in adult life remains problematic? 1 For all groups, accurate diagnosis means not only that of the fundamental condition but also an adequate description of all comorbidities, including behaviour problems and the potential for persistent additional psychiatric disorders which will in themselves interfere with future functioning. The clinical challenge is to manage these so that the effects are minimised rather than allconsuming, as is so often the case at the present time. Exciting progress is being made with regard to early detection although with considerable implications for services. Studies are now beginning to look at mediumto long-term outcomes and to measure comorbidities, but as yet although we have a little evidence on what is treatable we have very little evidence on what makes for effective prevention particularly of behaviour problems. REFERENCES

1. Bailey A, Phillips W, Rutter M. Autism: Towards an integration of clinical, genetic, neuropsychological and neurobiological perspectives. Journal of Child Psychiatry and Psychology 1996; 37 : 89-126. 2. Le Couteur A, Bailey A, Goode S et at. A broader phenotype of autism: The clinical spectrum in twins. Journal of Child Psychology and Psychiatry 1996; 37 : 785801. 3. American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, 4th Edn. (DSMIV). Washington, DC: American Psychiatric Association 1994. 4. World Health Organisation. Mental Disorders: A Glossary and Guide to their Classification in Accordance with the lOth Revision of the International Classificationof Diseases: Research Diagnostic Criteria (ICD-IO). Geneva: WHO 1993. 5. Wing L, Gould J. Severe impairments of social interaction and associated abnormalities in children: Indian Journal of Pediatrics, Volume 68---May, 2001

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